Method and apparatus for distillation



May 18 1926. 1,584,730

w. E. CHENQT METHOD AND APPARATUS FOR DISTILLA'I'IUN Filed p i 22 1924 2 Sheets-Sheet 1 William Edgar (enai ATTORNEYS May 1 8, 1926.

w. CHE'NOT METHOD AND APPARATUS FOR DISTILLATION Filed April 22,- 1924 -2 Sheets-Sheet 2 INVENTOR ATTORNEYS 10 a series of separate I Patented May 1 8, 2 1926 WILLIAM EDGAR CHENOT,

F BELLEVILLE, ILLINOIS.

METHOD AND APPARATUS FOR DISTILLATION.

Application filed April 22, 1924. Serial No. 708,150.

This invention relatesto animprovedmethed and apparatus for refining and fractionating. hydrocarbon oils. The invention relates, more particularly, to the separation and 5 recovery of gasoline or gasoline character fractions from oils such as crude petroleum,

distillates containing gasoline, and, the like.-

Hitherto, in refining-hydrocarbon oils it has been customary to subject the oil to distillations and redistillations to separate the oil into the fractions desired. The'initial separation is usually effected by simple distillation, but, on a commercial scale, the cuts so obtained are '15 not sufiiciently distinct, and it has been necessary to subject each of the ,separate fractions to a more or less extended series of further distillations in order to obtain cuts or fractions suitable for commercial purposes. Such further treatment has involved additional time, labor and apparatus.

Among the objectsof the present invention are the simple and direct separation of hydrocarbon oils into accurate fractions as desired in a single operation, theelimination of losses in the separation, andthe provision of a simple and efficient apparatus for effecting such separation.

According to this invention, hydrocarbon oils are subjected to a combined fractional distillation and fractional condensation treatment whereby the oil is fractionated or separated directly into accurate and 86 closely controlled cut-sin a single operation.-

According to the method of the invention, the condensate is subjected to asuccessive series of .distillations and condensa- 40 tions whereby the fraction or fractions finallv separated are of accurately defined boiling range; The oil is distilled'and the vapors are subjected to a dephlegmation treatment. The liquid condensate so obtain'ed is subjected to a revaporization treatment by heat interchange with the original body of oil undergoing distillation but without beinig brought into direct contact therewith. The vapors of the revaporized condensate are again subjected to a dephlegmation treatment and the condensate again subjected to a "revaporization treatment 5 original body-of oil in a similar manner. The vapors may be subjected to further process by heat interchange with the successive dephlegmation treatments and redistillation treatments 1n like manner where 1t is necessary or desirable to secure a more closely limited final fraction or a greater number of fractions. The vapors remaining after each dephlegmation treatment are withdrawn and collected without further contact with the oilundergoinlg distilla? tion or the vapors undergoing condensation in the successive steps of the operation. By directly returning for revaporization the condensate collected from the dephlegma: tion treatments Without substantial cooling below the pomt of condensation, the loss of heatinvolved in redistillation of the condensate is minimized. By removing the lighter vapors without permitting them to i recontact with the oil or oil vapors undergoing treatment, contamination of the vapors and decomposition or loss due to further heating of the vapors is avoided.

The process of the invention can be car-.

ried. out as a continuous process or as a ba-tchprocess. Where the processis carried out as a batch-operation, the end boiling point of thefinal vapors, after the last dephlegmation and revaporization, gradu ally increases as the operation proceeds and fractions of any desired boiling range can be separately collected by malfing succes sive cuts as the distillation progresses. Separate fractions may also be collected by withdrawing part of the intermediate condensate formed, during the operation.

is carrie out as a continuous operation,'the initial charge of oil undergoing disti'llation'is maintained by the additiorrof fresh oil thereto and the successive partial condensations are so regulated that the final vapors colleqted comprise the frac. tion of the desired composition. The character of this fraction may. be maintained substantially uniform throughout the operation' l'ntermediate fractions can be collected by Withdrawing part of the intermediate condensates or the unvaporized resi dues. The intermediate condensates are not Where the as accurately defined fractions as-thatfrac-. 1

lot

tions maybe required for separate cuts. In continuous operation, the fresh oil sup- .plied may be preheated, for example, by

heat exchange with residues or fractions withdrawn from the operation or by heat exchange with waste stack gases.

\Vhere the intermediate fractions separated during the operation are further fractionated, they may be treated in the same manner as the oil originally subjected to distillation, orthey may be redistilled in the ordinary manner. IVhere a higher yield of lower boiling fractions is desired. the intermediate and heavier fractions may be subjected to cracking treatment.

The apparatus of the invention comprises a still, a series of separate vaporizing receptacles adapted to be heated by the oil undergoing distillation in the still, a series of dephlegmators and means to conduct the vapors from the still and from each of the vapo rizing chambers except the last to one of the dephlegmators, means to conduct the condensate from each dephlegmator to the next vaporizing receptacle in the series and means to collect and remove the uncondensed vapors from each of the dephlegmators and from each vaporizing receptacle. In combination with a shell still, the apparatus of the invention may comprise two or more closed vaporizing receptacles within the still and below the normal liquid level therein, a series of dephlegmators, either above or to one side of the still, one communicating with the vapor space of the shell still and one with the vapor space of each of the vaporizing receptacles except the last,

connections for conducting the condensate,

rom the first (lephlegmator to the still, connections for conducting the condensate from the first dephlegmator to the second revaporizing receptacle, etc. Connections are also provided for withdrawing the remaining uncondensed vapors from each dephlegmator and from the last vaporizing receptacle without further contact or heat exchange with the partial condensate or the vapors undergoing condensation and conducting them to a final condenser. An addi tional dephlegmator may be interposed between the vapor space on the still and the first dephlegmator from which condensate is conducted to one of the separate vaporizing receptacles within the still, and connections provided for returning the condensate from this interposed dephlegmator directly to the still. The vapors from such an interposed dephlegmator are then conducted to the next dephlegmator and the vapors from the following .dephlegmators in the series separately collected and conducted away for condensation together with the vapors from the last vaporizing receptacle. The shell still may be supported and heated in a furnave housing of ordinary type but I find it more advantageous to arrange the shell still in a manner such that the entire surface of the still is subjected to the heating gases.

In the improved dephlegmator of the invention, the vapors are discharged downwardly through a series of equalizing perforations into an annular space adapted to be externally cooled and in which they undergo partial condensation. At the bottom of this annulus the flow of vapors is reversed, the downwardly moving particles or lilms of condensate separated, and the remaining vapors passed upwardly through a passage in the annulus but without substantial heat interchange with the vapors undergoing condensation therein. The dephlegmator may comprise a series of substanti ally concentric sheet metal cylinders, a circular pipe at the upper end of the outer two cylinders welded thereto and having a series of perforations opening downwardly into the space between the two cylinders and a vapor inlet connect-ion to the pipe, a wall of heat insulating material between the second and third cylinders and supported on an annular sheet metal ring welded to and closing the bottom of the second and third cylinders, and a vapor exit connection comnumicating with the interior of the third cylinder. IVhere the improved dephlegmator is employed superposed above a still, it may be arranged about a pipe projecting from the still passing centrally through the dephlegmator and surrounded within the dephlegmator by a suitable heat insulating wall.

The invention will be further described in connection with the accompanyingdrawings in which I have shown apparatus embodying the invention and adapted for use in carrying out the'process of the invention. It will be understood, however, that this specific illustration and the following description are for the purpose of illustrating the invention but that the invention is not limited thereby.

In the accompanying drawings:

Fig. 1 represents a fragmentary view, partly in-section and partly in elevation, of an improved distilling apparatus embodying the invention and adapted for use in carrying out the process of the invention,

Fig. 2 is a fragmentary end view, partly in section and partly in elevation, of the still structure shown in Fig. 1,

Fig. 3 is a vertical section of a modified form of dephlegmator embodying the invention.

Fig. 4 is a horizontal section on the line -l-'l of Fig. 1, and

Fig. 5 is an enlarged section of a modified form of connection for use between the still, or between the vaporizing receptacles therein. and the dephlegmator connected thereto.

Referring to the drawings, 1 is the primary still, in which the initial distillation takes place, and 2 is the dome of the pri- [safety appliances l mary still, communicating with the vapor space of the still, and through which the vapors escaping from the still pass.

' ing the still and adapted for conserving the heat of the'heating gases. The still is heated by hot products of combustion from a furnace (not shown) below the still in which coal, oil or products of combustion from the furnace pass around the surface of the still shell "and, after giving up their heat -to the oil within the still through the shell, escape through the stack flue 5. The top arch of the still housing 4 is supported upon angle irons 39 extending longitudinally of the still shell.

The dephlegmators above the still are in general of the same construct-ion and will be separately described only in so far as they differ from each other. in general,

7 1 the dephlegmatorscomprise a central pipe ders and pass downwardly terial, such as mineral 6, about which they through which'vapors pass, surrounded by a series of concentric sheet metal cylinders 7, 8, 9 and 10. "The vapors aredischarged into the dephlegmator through a circular pipe 11 at the upper end of the cylinders 9 and 10 through a series of perforations in the lower side of the pipe 11 in the space between the cylinders 9 and 10. The vapors entering the dephlegmator from the pipe 11 through the distributing and equalizing perforations are distributed throughout the annularv space between the outer two cylintherebetween. The outer cylinder 10 is closed at its lower end by means of the circular plate 12 which is sloped toward its outer edge to facilitate the collection andremoval of the condensate formed within the dephlegmator. The cylinders 8 and 9 are closed at their lower are supported and Y ends by means of an annular disc 13 welded thereto, and the space between these cylinders is filled with a suitable insulating ma- .wool or asbestos felt, to prevent the interchange of heat between the annular chamber between the cylinders 9 and 10 and the chamber enclosed by the cylinder 8. The uniform distribution of vapors maybe further promoted by the provision of perforated extensions on the disc 13 disposed across the annular spaces between the cylinders 7. and 8 and?) and 10 respectively; Thecylinder 7 is welded to the disc 12 at its lower end and extends upwardly through the cylinder 8, being closed at its upper end' by an annular *disc 1 The space between the cylinder 7 and the housing 4 entirely inclos-.

gas is burned. The hot' pipe 6 is filledwith heat insulating material and a small pipe 15 is provided communicating between the atmosphere and the space between the cylinder allow for expansion when the apparatus is heated up. The-cylinder 7 is closed after the insertion of theinsulating material. A' closure may also be provided at the upper end of the insulation between, cylinders 8 and 9 to; protect this insulation.

The diil'erences in the structure of the successive dephlegmators of the series will be pointed out in describing the path of the vapors therethrough. The flow of the va pors is indicated by arrows in the drawings. The vapors from the dome 2'on thep'rimary still enter the circular perforated pipe 11 in the first dephlegmator A through a pair of cross pipes 16 connecting the upper closed end of the pipe 6 and the circular pipe 11,

and'then pass downwardly through the 'externally cooled space between the cylinders 9' .and 10, undergoing partial condensation, the uncondensed lighter vapors passing downwardly through the perforations in the outer edge of the disc 13 and then upwardly through the inner tions through the'space between the cylinders 7 and 8 and escaping from the upper end thereof into the pipe 17. A valve 19 is provided in the connection between the pipe 17 and" the second dephlegmator B, which, in conjunction with valve 18, permits the separate withdrawal of the vapors from the first dephlegmator A through the valve 18. The vapors passing dephlegmator A through pp? 17 and valve 19 enter the circular distri uting pipe 11 at the top of the second dephlegmator B through connection 20. In the dephlegmator B the vapors flow downwardly between the cylinders 9 and 10," undergoing partial condensation, and the remaining uncondensed vapors pass .through the perforations--in the disc 13then upwardly between the cylinders 7 connection 21, The condensate formed in the first dephlegmator A is returned to the primary still through the pipe 22, which is provided with a trap to prevent the escape of vapors therethrough ithin the primary normal liquid level therein, lindrical revaporizing' receptacles, C are provided. The condensate second dephlegmator B is returned to the first revaporizing receptacle B connection 23 and the vapors from the receptacle B are passed "to the distributing pipe 11 in the third dephlegmator C through the connection 24, communicating with the vapor space in the receptacle B and the connection 25 connecting the upper end of the pipe 6 in the second dephlegmator B to which the pipe 24 connects.

still, and below the two closed cy- B and 7 and the pipe 6 to from the In the third ring. of perforafrom the first and 8 escapmg through the through 26. The condensate collecting in the third dephlegmator U is passed to the revaporizing receptacle C through connection 2?. The vapors from the revaporizing receptacle G pass upwardly through connection 28, communicating with the vapor space of the receptacle 0, and the pipe 6 in the third dephlegmator G. The vapors from the receptacle C and the unoondensed vapors escaping from the second and third dephlegmators, B and C. are thus mingled .in the connection 29 through which they are conducted to a linal condenser (not shown) of any suitable or approved form.

Dephlegmators of the construction illustrated in Fig. 1 are particularly adapted to be mounted above a primary still of the shell type. Where the dephlegmators are arranged away from the still or on supports separate from the still, a dephlegmator of the modified construction illustrated in Fig. 3 may be employed with advantage. In this dephlcgmator structure the vapors entering the dephlegmator through connection 30 are discharged downwardly in the space between the cylinders 9 and 10 through a circular distributing pipe 11' connecting the upper ends of and welded to the cylinders S) and 10. The cylinder 10 is adapted to be cooled externally and vapors passing downwardly between the cylinders 9 and 10- undergo partial condensation, the condensate collecting 'in the chamber formed by the circular-disc 12 welded to and clos.ng the lower end of the cylinder 10. The tottom 12 of the dephlemnator is dished inwardly slightly to facilitate the removal of the condensate through connection 22. The remaining uncondensed vapors pass upwardly through the central cylinder 8', and escape through connection 31. The lower ends of the cylindcrs 8- and 9' are closed by an annular disc 13 welded thereto, and a wall of insulating material is supported thereon between the cylinders 8' and 9'. The uniform distribution of vapors may be further promoted by the )rovision of a perforate extension on the disc 13 projecting across the space between the lower ends of the outer pairof cylinders and a perforate disc arranged over the lower end of the central opening. The wall of insulating material prevents heat exchange between the vapors passing upwardly through the central passage and the external annular passage in which partial condensation is effected.

Identical dephlegmators of this type may be substituted for the dephlegmators illustrated in Fig. 1', in which case the vapor inlet connection to each dephlegmator will be direct without passing through the preceding dephlegmator.

It will be noted, in either type of dephlegmator construction illustrated, that the vapors entering the dephlegmator are uniformly tllStlllHlLQtl throughout an annular cooled passage in which they pass downwardly while undergoing condensation, that in the bottom of this passage the flow of uncondensed vapors is abruptly reversed, facilitating the separation of the downwardly moving particles or films of liquid condensate from the uncondensed vapors, that uniform distribution of the vapors is maintained and that the lighter uncondensed vapors escape upwardly through the central passage without further contact with the liquid condensate or the vapors undergoing condensation and without heat interchange therewith.

The piping connecting the dephlegmators and the still and vaporizing receptacles for carrying the vapors to and from the dephleginators and returning the condensates formed therein may be insulated to prevent, or reduce heat losses. The condensation within each dcphlegmator may also be regulated, witlnn limits, by shielding or partially insulating the external cooling surface of the chamber within which condensation 4 is effected in the de )hlegniator, particularly during cold weather.

A connection maybe provided at the lower end of pipe 6 for withdrawing part of the vapors passing to each of the dephlcgmators in the series where it is desired to subject a part of the vapors to separate treatment, or where the operation is elfected 21s a batch process and it is desired to bypass a part of the vapors during part of the period of operation. This connection may he of the construction illustrated in Fig. 5, which is adapted to remove a part of the vapors and also to remove any liquid condensed within the pipes 6. In this construc tion, the vapors enter the chamber 32 through the connection 33, which communicates with the still or vaporizing receptacle, and pass about the battle 34 upward y through the pipe 6. Part of the vapors may be withdrawn through connection 35 and regulation of the part withdrawn may be effected by means of valve 36. The ballle 3% is arranged above an extension 37 of the pipe 33 into the chamber 32. Any condensate collecting in the pipe 6 is thus directed into the space about the projection 3.7 and may be withdrawn through the valved connection 38. o

The primary still 1, is provided with a valved draw-off 40 and a. connection for the ill) ' pacity of introduction of fresh stock 41. Each of the vaporizingreceptacles, B provide'd'with valved draw-offs, 42 and 43 respectively, for the removal of residues or heavy fractions therefrom.

In carrying out the method of the invention as a batch operation in the apparatus illustrated, for example, for the production of gasoline from crude oil, crude oil is fed into the still lthrough connection 41 up to about. 80% of the volumetric cathe still shell. Heat is then applied to the stilland the vapors rise passing upwardly 6 communicating therewith into the condensing space between the outer two cylinders in the first dephlegmator A through the equalizing and distributing perforations in the pipe 11. The'vapors pass downwardly between the cylinders 9 and 10 in the first dephlegmator A, undergoing partial condensation therein, the condensate being returned to the still 1 through back-trap connection 22, the uncondensed vapors escaping through the equalizing'and distributing perforations in the disc 13 then upwardly through the space between cylinders 7 and 8 to the second dephlegmator B through connections 17 and 20 and the valve 19. In the second dephlegmator B, a second grading by partial condensation takes place in a similar manner, the condensate being returned to the revaporizing receptacle B through connection -23 and the uncondensed vapors escaping through connection 21. The condensate is returned to the revaporizing receptacle B while hot and at a temperature just below the critical point at which condensation takes place and is redistilled in the receptacle B by the heat transferred through the walls of the vaporizing recep tacle from the oil in the still but without cumin in contact with the oil in the still. The hght, uncondensed and clean vapors pass out through the connection 21 to the final condenser without further contacting with the condensate or the vapors undergo- C escape through the apertures 26 ing condensation. The vapors of the revaporiz'ed condensate from the receptacle B pass upwardl through connection 25, into the third dep legmator C, in which a third grading by partial condensation takes place The uncondensed or cleaned vapors from the third dephlegmator into the vapor 1ine-to the final condenser. The con- 3' through I subjectedto redistillation. 'The vapors densate collected in the third dephlegmator C is returned to the vaporizing receptacle connection 27 where it is again from the condensate. re v aporized in the receptacle (3' pass upwardly through connecdiiser. The inicondensed-vapors from the dephlegmatorsB and C 'andthe Vapors and C, are also through the dome 2 and the pipe trolled.

from the redistilling' compartment C are mingled in the vapor line 29 whence they pass to final condensation. As lation proceeds, the vapors escaping through the connection 29 gradually become heavier.

By the use of suitable temperature measuring instruments, or by. measuring the gravity tinal condenser, the first cut is separately collected until the .end boiling point of the desired gasoline fraction is reached, for example,,420? F. Thereafter'the distillation may be continued for the production of illuminating oils or other fractions. The

fractions so collected may be subjected to the distilof the condensate collected in the further treatment, and may be cracked for :he further production of lighter distillates. The vapors of the heavier fractions may be subjected to vapor phase cracking, and for this purpose, it is advantageous to conduct the vapors from the still, either through connection 36 or through valved connection 18 by opening the valve 18 and closing the valve 19, directly to the vapor phase cracking apparatus without intermediate cooling.

In carrying out the method of the invention as a continuous operation in the apparatus illustrated, for the production of gasoline, the still charge is maintained by the introduction of fresh stock through the inlet 41, either continuously or intermittently, as

the distillation proceeds. The fresh stock so introduced is advantageously preheated. To

control the operation, the still may be equipped with suitable gauges-to indicate the oil level and with temperature measuring instruments to indicate the thermal conditions prevailing in the still. By regulating the firing of the still, the character of the vapors escaping through the vapor line 29 is con- This regulation may be supplemented by regulation of the partial condensation effected in the dephlegmato'rs,-as before pointed out. The heavy residue collecting in the primary still 1 and the unvaporized residues or heavier fractions collecting in the vaporizing receptacles B and C are withdrawn as the operation progresses through connectionsflO, 42 and 43 respectively. In continuous operation, the connection 40 is advantageously equipped withan inverted. U-pipe forming a trap to automatically maintain the desired oil level in the still, and the outlets 42 and 43 from the va orizin rece tacles B and C ma be provided with traps to prevent the escape of vapors therefrom. The residue i from the primary still, to which the residues from the redistilling compartments B and. C :may be. i

conducted to a second still,

oil out and a gas oil out, for example, the second still can be of the construction illustrated, and the third still for the separation of the gas oil fraction, may be an ordinary shell still. The vapors from the illuminating oil still and the gas oil still may be subjected without intermediate condensation, to vapor phase cracking treatment. Lubricating oil fractions may also be separated from the residues by further distillation. The fractionation of the crude oil into several cuts may likewise be effected in a single still of the character illustrated, and the several fractions withdrawn as unvaporized residues from the primary still 1 and each of the separate vaporizing receptacles.

It will be apparent, that additional redistillation compartments and additional dephlegmators may be employed, either to obtain a more accurate final cut, or for the purpose of obtaining in a single operation, a greater number of separate cuts or fractions.

It will thus be seen that this invention provides an improved process and apparatus which provides economy in operation in saving time and labor involved in redistillation for example over the customary redistillation with steam, while at the same time an accurate, sweet and clean fraction is obtained. Losses in condensation are reduced or eliminated, particularly as compared to the usual uncondensed steam still vapor loss. The lightest and cleanest vapors are immediately removed without being subjected to unnecessary heating, thereby avoiding losses through the formation of fixed gases or difficulty condensible vapors. The final product is effectively redistilled two or more times without the heat losses involved Where each fraction is cooled before being subjected to redistillation, and the fractions redistilled and the redistilled vapors are kept free from contact with the oil or vapor from which they have been previously separated. Due to the plurality of fractional distillations and ,fractional condensations etfected, the distillation may be ushed and high capacity obtained. without etriment to the quality of the product obtained.

\Vhile the invention in particularly applicable to refining and separating gasoline character fractions and similar light fractions, it will be apparent that the invention may be employed in connection with the separation and treatment of heavier fractions, for example, kerosene or gas oil. From average crude oil of good quality, a clean sweetand water white gasolinefraction as distilled can be separated without chemical treatment.

I claim:

1. An improved method of distilling hydrocarbon oils, which comprises initially distilling the original oil, ephlegmating the vapors, redistilling the condensate obtained by this dephlegmation by heat interchange with the original oil undergoing distillation but without direct contact therewith, and collecting in a common receiver the uncondensed vapors from the dcphlegmation and the vapors of the redistilled condensate obtained from the redistillation without contacting them with the oil being distilled, the said condensate, or the vapors undergoing dephlegmation.

2. An improved method of distilling hydrocarbon oils, which comprises initially distilling the original oil, dephlegmating the vapors, redistilling the condensate obtained by this dephlegmation by heat interchange with the original oil undergoing distillation but without direct contact therewith, and collecting in a common receiver the uncondensed vapors from the dcphlegmation and the vapors of the redistilled condensate obtained from the redist-illation without bringing them in contact or heat exchanging relation with the oil being distilled, the said condensate, or the vapors undergoing dephlegmation.

3. An improved method of distilling hydrocarbon oils, which comprises initially distilling the original oil, dephlegmating thevapors, redistilling the condensate obtained by this dephlegmation by heat interchange with the original oil undergoing distillation but without direct contact therewith. dephleginaring the vapors from the redistillation,redistilling the condensate from the 'second dephlegmation by heat interchange with the original oil undergoing distillation but without direct contact therewith and collecting in a common receiver the uncondensed vapors from each dephlegmation and from the second redistillation without contacting them with the oil being distilled, the said condensates, or the vapors undergoing dephlegmation.

4. An improved method of distilling hydrocarbon oils, which'comprises initially distilling the original oil, dephlegmating the vapors, redistilling the condensate so obtained by heat interchange with the original oil undergoing distillation but without direct contact therewith, dephlegmating the vapors from the redistil'ation, redistilling the condensate from the second dephlegmationby heat interchange with the original oil undergoing distillation but without direct contact therewith, and collecting in a common receiver the uncondensed vapors from each dephlegmation and from the second redistillation without bringing them in contact or heat exchanging relation with the oil being distilled, the said condensates, or the vapors undergoing dephlegmation.

5. An improved method of distilling hydrocarbon oils, which com rises initially distilling the original oil, ephlegmating the fronreach dephlegmator to the next vaporii pors of vapors, returning the condensate to the initial distillation, subjecting the uncondensed vapors to a second dephle 'mation, redistilling the condensate obtaine -trom the second dephlegniation byheat interchange with the original oil undergoing distillation but Without direct contact therewith, and collecting in a common receiver the uncondense'd vapors from the second dephlegmation and the vacontacting them with the oil being distilled, the said condensates, or the vapors undergoing dephlegmation.

6. Animproved apparatus. for distilling hydrocarbon oils, comprising a 'still, a series of closed vaporizing receptacles within the still, a series of dephlegmators and means for conducting the vapors from the still and from each of the vaporizing receptacles except the last to one of the said dephlegmators, means for conducting the condensate izing receptacle in the series, a commonreceiver for vapors from the dephlegmators and the last vaporizing receptacle and means for collecting and removing the uncondensed vapors from each of the said dephlegmators and the vapors from the last vaporizing receptacle to said common receiver.

7, An improved apparatus for distilling hydrocarbon oils, comprising a shell still, a series of closed vaporizing receptacles within the still and below the normal liquid level therein, a series of dephlegmators, a

connection between the vapor space of the still and the first dephlegmator, connections between the vapor space of one vaporizing receptacle other than the last and one of the said dephlegmators "other than the first, connections for conducting condensate from each dephlegmator to the next vaporizing receptacle, and a common vapor lme communicating with the last vaporizing receptacle and each of the said d-ephlegmators.

An improved apparatus for distilling hydrocarbon oils, comprising a shell still, a

series of closed vaporizing receptacles with in the still and below the normal liquid level therein and a series of dephlegmators,

connections for conducting-the liquid condensate from each of the dephlegmators to the next vaporizing receptacles, a separate de vihlegmator communicating with the vapor the redisti-lled condensate without space of the still having a connection for; returning condensate to the still, a vapor connection between said last named dephlegmator and the first dephlegmator in, said first named series, connections communi-- eating with the vapor space of one of the; vaporizing receptacles other than the last. for conducting vapors to the next dephleginator in the first named series, a common receiver for vapors from the dephlegmators and the lastlvaporizing receptacle, and connections for conducting away the vapors from the; last vaporizingrreceptade and from each of the dephlegmators in the first named series to said common receiver,

9. An improved apparatusfor distilling hydrocarbon oils, comprising a still, a series of separate vaporizing receptacles within the still, a series of dephlegmators and'means for conducting the vapors from the still and from each of the vaporizing chambers except the last to one of the said dephlegmators, means to conduct the condensate from each dephlegmator to the next vaporizing receptacle in the series, a common receiver for vapors from the dephlegmators and the last vaporizing receptacle, means to collect and remove the uncondensed vapors from each of the dephlegmators and from the last vaporizing receptacle to said common receiver, and a dephlegmator interposed in s the vapor connection between the still and the first dephlegmator of said series hav ing a connection for returning condensate to the still. i

10. An improved method of distilling hydrocarbon oils, which comprises initially distilling the original oil, dephlegmating the vapors, redistilling the condensate obtained by this dephlegmation by heat interchange with the original oil undergoing distillation but Without direct contact there with and collecting in a common receiver and subjecting to final condensation the uncondcnsed vapors from the ,dephlee mation and the vapors of the reva-porized condensate from'the redistillation Without contacting them with the oil being distilled, the said condensate, or the vapors undergoing dephlegmation. v

In testimony whereof I afiix my signature.

\VILLIAM EDGAR CHENOT.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,584,! 30, granted May 18, 1926, upon the application of William Edgar Chenot, of Belleville, Illinois, for an improvement in Methods and Apparatus for Distillation, an error appears in the printed specification requirin correction as follows: Page 2, strike out line 41 and insert instead the second depzlegmator 230 the first remand that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealedthis 13th day of July, A. D. 1926.

[SEAL] M. J MOORE,

' Acting Commissioner of Patents. 

